Bi-allelic loss-of-function OBSCN variants predispose individuals to severe recurrent rhabdomyolysis.

Rhabdomyolysis is the acute breakdown of skeletal myofibres in response to an initiating factor, most commonly toxins and over exertion. A variety of genetic disorders predispose to rhabdomyolysis through different pathogenic mechanisms, particularly in patients with recurrent episodes. However, most cases remain without a genetic diagnosis.

Energy metabolism during exercise in patients with β-enolase deficiency (GSDXIII).

Aim: To investigate the in vivo skeletal muscle metabolism in patients with β-enolase deficiency (GSDXIII) during exercise, and the effect of glucose infusion.

Methods: Three patients with GSDXIII and 10 healthy controls performed a nonischemic handgrip test as well as an incremental cycle ergometer test measuring maximal oxidative consumption (VO) and a 1-hour submaximal cycle test at an intensity of 65% to 75% of VO. The patients repeated the submaximal exercise after 2 days, where they received a 10% iv-glucose supplementation.

Longitudinal observational study investigating outcome measures for clinical trials in inclusion body myositis.

Objective: To describe decline in muscle strength and physical function in patients with sporadic inclusion body myositis (IBM).

Methods: Manual muscle testing (MMT), quantitative muscle testing (QMT) and disability scoring using the IBM Functional Rating Scale (IBMFRS) were undertaken for 181 patients for up to 7.3 years.

Paediatric myasthenia gravis: Prognostic factors for drug free remission.

Our aim was to identify clinical outcomes, serological features and possible prognostic indicators of paediatric myasthenia gravis (MG). We collected 74 MG patients with disease onset before the age of 16 years (73% pre-pubertal onset defined as ≤10 years), seen regularly at two UK specialist centres, over a period of 11 years. The cohort was multi-ethnic, with a high number of non-Caucasians (52%).

The need for biochemical testing in beta-enolase deficiency in the genomic era.

Glycogen storage disease type XIII (GSDXIII) is a very rare inherited metabolic myopathy characterized by autosomal-recessive mutations in the gene resulting in muscle β-enolase deficiency, an enzymatic defect of the distal part of glycolysis. Enzyme kinetic studies of two patients presenting with exertion intolerance and recurrent rhabdomyolysis are reported. Next generation sequencing confirmed patient 1 was homozygous for p.

Idiopathic inflammatory myopathy: Interrater variability in muscle biopsy reading.

Objective: To determine interrater variability in diagnosing individual muscle biopsy abnormalities and diagnosis.

Methods: We developed a scoring tool to analyze consensus in muscle biopsy reading of an ad hoc workgroup of international experts. Twenty-four samples from patients with suspected idiopathic inflammatory myopathy (IIM) were randomly selected, providing sections that were stained with standard histologic and immunohistochemical methods.

Statin-related myopathies.

Statins are the Marmite ('You either love it or hate it!') of the drug world, both in terms of therapeutic benefit and risk of side effects. Proponents think that they are potential life-savers, opponents that their main benefit is lining the pockets of pharma. Some consider side effects to be a major issue, outweighing any therapeutic benefit, others that they are rare and essentially innocuous.

TIA1 variant drives myodegeneration in multisystem proteinopathy with SQSTM1 mutations.

Multisystem proteinopathy (MSP) involves disturbances of stress granule (SG) dynamics and autophagic protein degradation that underlie the pathogenesis of a spectrum of degenerative diseases that affect muscle, brain, and bone. Specifically, identical mutations in the autophagic adaptor SQSTM1 can cause varied penetrance of 4 distinct phenotypes: amyotrophic lateral sclerosis (ALS), frontotemporal dementia, Paget's disease of the bone, and distal myopathy. It has been hypothesized that clinical pleiotropy relates to additional genetic determinants, but thus far, evidence has been lacking.

Thymus imaging in myasthenia gravis: The relevance in clinical practice.

Introduction: The ability to distinguish between normal thymus, thymic hyperplasia, and thymoma should aid clinical management and decision making in patients with myasthenia gravis (MG). We sought to determine the accuracy of routine imaging in predicting thymic pathology.

Methods: We retrospectively analyzed records of patients with MG from the Oxford Myasthenia Centre registry who had undergone thymectomy.

Ataxia with oculomotor apraxia type 2: an evolving axonal neuropathy.

A 23-year-old woman had presented initially to a podiatrist complaining of poorly fitting shoes during her adolescence. After extensive neurological review, she was diagnosed with ataxia with oculomotor apraxia type 2. This is a progressive autosomal recessive ataxia associated with cerebellar atrophy, peripheral neuropathy and an elevated serum α-fetoprotein.

The Association of British Neurologists' myasthenia gravis guidelines.

Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction for which many therapies were developed before the era of evidence-based medicine. Despite the basic principles of treatment being well known, patients continue to receive suboptimal treatment. A myasthenia gravis guidelines group was therefore established under the aegis of the Association of British Neurologists.

Chronic pain has a strong impact on quality of life in facioscapulohumeral muscular dystrophy.

Introduction: Earlier small case series and clinical observations reported on chronic pain playing an important role in facioscapulohumeral dystrophy (FSHD). The aim of this study was to determine the characteristics and impact of pain on quality of life (QoL) in patients with FSHD.

Methods: We analyzed patient reported outcome measures collected through the U.

IgG-specific cell-based assay detects potentially pathogenic MuSK-Abs in seronegative MG.

Objective: To increase the detection of MuSK-Abs using a CBA and test their pathogenicity.

Methods: Sera from 69 MuSK-RIA-positive patients with myasthenia gravis (MG) (Definite MuSK-MG), 169 patients negative for MuSK-RIA and AChR-RIA (seronegative MG, SNMG), 35 healthy individuals (healthy controls, HCs), and 16 NMDA receptor-Ab-positive (NMDAR-Ab) disease controls were tested for binding to MuSK on a CBA using different secondary antibodies.

Results: Initially, in addition to 18% of SNMG sera, 11% of HC and 19% of NMDAR-Ab sera showed positive binding to MuSK-transfected cells; this low specificity was due to anti-IgG(H+L) detection of IgM bound nonspecifically to MuSK.

The UK Myotonic Dystrophy Patient Registry: facilitating and accelerating clinical research.

Myotonic dystrophy type 1 (DM1) is the most frequent muscular dystrophy worldwide with complex, multi-systemic, and progressively worsening symptoms. There is currently no treatment for this inherited disorder and research can be challenging due to the rarity and variability of the disease. The UK Myotonic Dystrophy Patient Registry is a patient self-enrolling online database collecting clinical and genetic information.

Mortality and Causes of Death in Patients with Sporadic Inclusion Body Myositis: Survey Study Based on the Clinical Experience of Specialists in Australia, Europe and the USA.

Background: There is a paucity of data on mortality and causes of death (CoDs) in patients with sporadic inclusion body myositis (sIBM), a rare, progressive, degenerative, inflammatory myopathy that typically affects those aged over 50 years.

Objective: Based on patient records and expertise of clinical specialists, this study used questionnaires to evaluate physicians' views on clinical characteristics of sIBM that may impact on premature mortality and CoDs in these patients.

Methods: Thirteen physicians from seven countries completed two questionnaires online between December 20, 2012 and January 15, 2013.

Rare variants in SQSTM1 and VCP genes and risk of sporadic inclusion body myositis.

Genetic factors have been suggested to be involved in the pathogenesis of sporadic inclusion body myositis (sIBM). Sequestosome 1 (SQSTM1) and valosin-containing protein (VCP) are 2 key genes associated with several neurodegenerative disorders but have yet to be thoroughly investigated in sIBM. A candidate gene analysis was conducted using whole-exome sequencing data from 181 sIBM patients, and whole-transcriptome expression analysis was performed in patients with genetic variants of interest.

CAV3 mutations causing exercise intolerance, myalgia and rhabdomyolysis: Expanding the phenotypic spectrum of caveolinopathies.

Rhabdomyolysis is often due to a combination of environmental trigger(s) and genetic predisposition; however, the underlying genetic cause remains elusive in many cases. Mutations in CAV3 lead to various neuromuscular phenotypes with partial overlap, including limb girdle muscular dystrophy type 1C (LGMD1C), rippling muscle disease, distal myopathy and isolated hyperCKemia. Here we present a series of eight patients from seven families presenting with exercise intolerance and rhabdomyolysis caused by mutations in CAV3 diagnosed by next generation sequencing (NGS) (n = 6).

Prevalence of Pompe disease in 3,076 patients with hyperCKemia and limb-girdle muscular weakness.

Objective: We prospectively screened a large European cohort of patients presenting with hyperCKemia and/or limb-girdle muscular weakness (LGMW) for acid α-glucosidase (GAA) deficiency by dried blood spot (DBS) investigation.

Methods: DBS were collected from 3,076 consecutive adult patients from 7 German and British neuromuscular centers. All specimens were investigated for GAA deficiency by fluorometry.

Design, set-up and utility of the UK facioscapulohumeral muscular dystrophy patient registry.

Facioscapulohumeral dystrophy (FSHD) is a rare inherited neuromuscular disease estimated to affect 1/15,000 people. Through basic research, remarkable progress has been made towards the development of targeted therapies. Patient identification, through registries or other means is essential for trial-readiness.

A protocol to develop clinical guidelines for inclusion-body myositis.

Introduction: Inclusion-body myositis (IBM) is a late-onset idiopathic inflammatory myopathy associated with selective and progressive muscle weakness and atrophy. Current clinical management of IBM is largely supportive due to its uncertain etiology and lack of effective treatment. Establishing a consensus of opinion on questions relating to diagnosis and management of IBM is expected to help reduce inconsistencies in the care and resources allocated to those living with this condition.

A novel quantitative assay of mitophagy: Combining high content fluorescence microscopy and mitochondrial DNA load to quantify mitophagy and identify novel pharmacological tools against pathogenic heteroplasmic mtDNA.

Mitophagy is a cellular mechanism for the recycling of mitochondrial fragments. This process is able to improve mitochondrial DNA (mtDNA) quality in heteroplasmic mtDNA disease, in which mutant mtDNA co-exists with normal mtDNA. In disorders where the load of mutant mtDNA determines disease severity it is likely to be an important determinant of disease progression.

Genotype/phenotype correlations in AARS-related neuropathy in a cohort of patients from the United Kingdom and Ireland.

Charcot-Marie-Tooth disease (CMT) is the most common inherited neuropathy with heterogeneous clinical presentation and genetic background. The axonal form (CMT2) is characterised by decreased action potentials indicating primary axonal damage. The underlying pathology involves axonal degeneration which is supposed to be related to axonal protein dysfunction caused by various gene mutations.

Myasthenia gravis: Association of British Neurologists' management guidelines.

Myasthenia gravis is an autoimmune disease of the neuromuscular junction for which many therapies were developed before the era of evidence based medicine. The basic principles of treatment are well known, however, patients continue to receive suboptimal treatment as a result of which a myasthenia gravis guidelines group was established under the aegis of The Association of British Neurologists. These guidelines attempt to steer a path between evidence-based practice where available, and established best practice where evidence is unavailable.

Clinical Features and Diagnostic Usefulness of Antibodies to Clustered Acetylcholine Receptors in the Diagnosis of Seronegative Myasthenia Gravis.

Importance: Cell-based assays (CBAs) were shown to improve detection of acetylcholine receptor (AChR) antibodies in patients with myasthenia gravis (MG). Herein, we asked whether these assays were able to help determine the diagnosis in patients studied in routine clinical practice.

Objectives: To determine the diagnostic usefulness of CBAs in the diagnosis of MG and to compare the clinical features of patients with antibodies only to clustered AChRs with those of patients with seronegative MG (SNMG).